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It was recently shown that a strong Landau diamagnetism may emerge in strongly correlated electron systems (SCES) under nonequilibrium steady state (NESS) conditions. However, due to high resistivity of the insulating state, in situ sign-switching of magnetism was not possible in the previous study. Here, we demonstrate that DC current can trigger in situ switching between the impurity-induced Mott insulating state and diamagnetic semimetallic state of the bilayered ruthenate Ca₃Ru₂O₇. By performing simultaneous magnetic and resistive measurements, we map out the temperature vs current-density phase diagram in the NESS of this material. The present results open up the possibility of creating novel electronic states in a variety of SCES by NESS conditions under DC current.